A David and Goliath story is playing out on the African savanna, where tree-loving ants are fending off herds of tree-hungry elephants, proving that - in nature - size and strength don't always triumph.Florida biology professor Todd Palmer studied the curious interaction between ants and elephants in one area of the savanna in Kenya where the Acacia are thriving. The plant has a tough time taking root because of the thick clay soil and the threat of roving elephants who dine on the trees' leaves and bark, leaving many stripped bare.